Die head for multiple extrusion



sept., 25, 1951 P. PAY 2,569,373

DIE HEAD FOR MULTIPLE EXTRUSION Filed Sept. 21, 1948 3 Sheets4Sheet l um v INVENTOR Pfff/176A fly ORNEY Sept. 25, 1951 P, FAY

DIE HEAD FOR MULTIPLE EXTRUSION 3 Sheets-Sheet 2 Filed Sept. 21, 1948 w mi@ MMP@ Mw sept. 25, 1951 p. PAY 2,569,33

DIE HAD FOR MULTIPLE EXTRUSION Filed sept. 2l,`1948 s sheets-sheet s TORNEY Patented Sept. 25, 1951 UNITED) YSTATES :PATENT orifice DIE HEAD .FOR' MULTIPLE AEX'IRUSION Patrick say, Detroit, Mich., assignor to United States lRubber Company, New York, N. Y., a corporation `of New Jersey Application september 21,1948, vserial No. 50,327

' (ci. 1ra- 13) 1v This invention relates to Van apparatus for exytruding -plastic materials and, in particular, Ait relates to -a die head for association with multir*ple/tubers for -extruding a composite product of resilient material. f V Y 'in the manufacture of pneumatic tires, it is customary to extrude certainfcomponents of the pneumatic 4tire'such -as the tire tread.- In many cases, itis 4desirable to formthe tread fofarubber, lor' synthetic rubber, composition and f in which different compositions-are used r-in difyferent portions of the tread.- For example, the wear'resisting portion of the tread maybe formed of one composition, .While the adjoining portions and side wall portions mayl -be formed of a different composition. Still further, the -use of` different colors in the composition is sometimes ldesirable such as in the formation of Ywhite side Wall tires. f Y' In 'the manufacture yof white side wall tires, it has been general practice to form the princi- .pal v tread :portion by the extrusion method. A -white side wall strip is also extruded but in a separate operation.' "Thereafter the black tread .portion andthe white sidewall portion-are bond- .'ed togetherin spliced'rlationship. This is largely aimanual task and the uniformity of the splice is not very satisfactory. The splice is frequently irregular -in appearance and vfrequently separates during the manufacturing operation.

In accordance with the practice of my invenrt'ion, I provide an apparatus in the form of atuber d ie Ahead which is capable of forming an integral 'tires 'and different designs of the same size tires.

Accordingly, I provide within` the tuber die head an adjustable means jfor varying the locationof lthe line'of demarcation between the Whiteand black rubber compositions.

' The invention, therefore, contemplates an apparatus for forming tire treads fromy three different rubber compositions, including an adinstable positioning of a white or other colored rubber composition relative to the black compo- 14 Claims.

sition. `By this arrangement, it is possible to form a splice between the two compositions which will not separate during or after manufacturing operations. Uniformity in the positioning of the splice is also obtained. Furthermore, a reduction in labor is accomplished thereby making -it possible to provide a better product on a more economical basis.

These and other objects and advantages will appear more zfully in the followingdetailed description when considered in connection with the accompanying drawings in which:

Figure 1 is aV plan view of a complete assembly of an extrusionapparatus embodying vthe features of my invention;

Figure 2 is a transverse View in section of a composite tread which -is the resulting product of the apparatusof my invention;

IFigure 3 is an enlarged plan view of a tuber die head; i

Figure 4 is a .transverse `View `in lsection of a `tulcer die head taken along lines IV-IV of Figticular, Yto Figure 1, I show an embodiment of `my invention includingv a pluralityoftubers or extrusion devices. Each of these tubers. is of conventional Ydesign and consists generally -of a heavy duty motor-capable ofdriving a feed screw positioned within -a housing for the' purpose of eXtrud-ing plastic material through aXed die.

As'fsho'wn in Figure 1,- the three ltuber units are identified by the reference characters A, B and C. The tuber A comprises essentially a f-h'ousing I and a heavy duty motor 2 adapted to drive a conventional feed screw within lthe housing 0l. A feed opening'3 above the feed screw in the housing l provides for ther-entrance of rubber Vstock into the tuber. This rubber stock is usually supplied in the form of a continuous strip or ribbon.

The tuber 'B is videntical With the tuber A in that it includes a housing 4, a motor 5 and a feed opening.Y The tubers A and B are opposed to eachother and their extruding'ends communicate with a common die head 1. As appears in,

intended that the tuber C extrude a smaller strip, the tuber may be of smaller size and capacity. This tuber C also joins with the common die head 1 and at a point to one side of the horizontally opposed tubers A and B.

The resulting product of the tuber combination is illustrated in Figure 2. This shows a transverse view of a tread adapted for application to a pneumatic tire. The tread consists of different components including a tread portion I I formed. of a particular rubber composition embodying wear resisting characteristics. One side of the tread constitutes a side wall portion I2. This portion also extends underneath the tread I I and is referred to as a subtread I3. The composition of the portions I2 and I3 are similar and are particularly adapted to suit the requirements of the side wall portion of a tire and also the subtread which is not subjected to abrasion. That portion of the tread which is opposite the side wall portion I2 is formed of a different rubber composition I4. A particular example of the composition of the side wall portion I4 is a white rubber stock such as used in the formation of white side wall tires. This combination of rubber stocks results in the formation of a pneumatic tire having one white side wall and one yblack side wall. The junction I5 denes the line of demarcation between the white stock I4 and 1 combinations thereof, or other plastic materials .which are capable of being extruded.

- The tuber head assembly is shown particularly in Figures 3 and 4. The tuber head is connected to `each of the tubers or extruders A. B and C. Horizontal cavities in the tuber head are connected with the respective extruder and merge with each other at a common opening at right angles thereto to form the composite tread as shown in Figure 2. The tuber head 1 is formed principally of an upper and lower portion 5I and I6, respectively. Cavities I1, I8 and I9 connect with the tubers A, B and C, respectively, and are formed, in part, in the upper and lower portions 5I and I6 of the tuber head 1. Bolts 28 lfasten securely together the upper and lower vportions 5I and IE of the tuber head. The upper portionl of the tuber head is provided with chambers 2| and 22. Inlet and outlet conduits 23 and 24, respectively, permit water to be circulated through the chambers 2| and 22 so as t0 control the temperature of the tuber head. An opening 25 provides communication between the two chambers 2| and 22.

The lower portion I6 of the tuber head is also provided with chambers 26 and 21 which communicates with conduits 28 and 29 allowing for circulation of water for maintaining the tuber head at the desired temperature. The cavity I1 enters the die head 1 horizontally to form a cavity which bends downwardly and fans sideways so that the cavity forms in effect an elongated slot near the bottom portion of the die head. The cavity I8 connecting with the tuber B also .provides an opening near the bottom of .the die head in the form of an elongated slot.

The axial centers of the cavities I1 and I8, as well as the axial centers of the tubers A and B, are oiset as appears in the plan view of Figure 3. The purpose of this oiTset relation is to permit a greater quantity of stock from the cavity I1 to be disposed on one side of the tread so as to constitute the portions I2 and I3 of the extruded tread. The cavity I8 is intended to form the tread portion II while the cavity I9 completes the tread by supplying the white rubber composition I4 for forming one of the side Walls of the tread.

'I'he line of demarcation indicated by the numeral I5 forms the junction between the white and black rub-ber compositions. Since it is necessary to locate this line of demarcation at different places along the side Wall of the tread in order to accommodate different size tires and different design tires, it is essential to provide an adjustable means for varying the position of the line of demarcation I5. This is accomplished by .providing a triangular shaped bar 30 adapted to extend the full length of the die opening and to form, in particular, a continuation of the walls of the cavities I1, I8 and I9.' A flat portion or base 30 of the triangular member 30 rests against the underside of the upper portion 5I of the die head. The adjacent ilat surfaces forming the continuation of the die head cavities terminate, and the various rubber compositions merge together, at the apex of the triangle of the member 3B. Y A block 3| is attached to the triangular member 30 by means of machine screws 32. A part of the block 3| is tapered at 33 (Fig. 7) `for defining the line of demarcation I5. The block 3| serves to form a wall between the cavities I1 and I9. By moving the triangular member 30 in a lengthwise direction, the block 3| which is attached thereto likewise moves and accordingly constitutes a wall variable in position between the cavities I1 and I9.

For adjusting the block 3| a pair of plates 34 and 35 are attached to the lower die head portion I6. These plates'retain an adjusting screw 3B having a hexagonal shaped end portion 31 to which a hand tool may be applied for turning the screw 36 and adjustably moving the block 3|. Screw threads 38 are .provided at one end of the triangular member 3U for complementary engagement with the adjusting screw 36.

Since the triangular member 30 constitutes a relatively heavy block of metal, it is desirable to provide a cooling means or a means for heating the member during its initial operation. To accomplish this a bore 39 is formed in the triangular member 30 and a conduit-40 is extended therein to almost its entire length. A plate 4I closes the open end of the bore and another opening 42y is provided through the plate 4I. By this arrangement water may be introduced into the opening 42 and circulated out through the conduit 40. Thus, a temperature control may be maintained in respect to the triangular member 30.

The cavity openings near the lowermost portion of the die head communicates with a preforming die 43. This preforming die includes a single cavity 44 throughfwhich the rubber stocks from the various cavities I1, I8 and I9 are forced. The preforming die converges the rubber cornposition in proper position to the final die 45. The final die 45 consists of a flat plate having an opening cut into one side substantially in accordance with the profile of the tread as shownr in Figure 2'.V Both the preforming die and the. Vfinal "arefheldn'placeby va-plurality of clamps-46 land bolts ffl'l.- j A urt'her `adjustment attached -to the pre- 'foifmng dit-:'43 is Aa jproportioning pla-te 48 attached tothe preforming die Iby'mac'hine screws 4 3. Slots 5 0 in `the proportioning plate allow for adjustment of the plate Vto narrow or enlargefthe .cavity at ,this point.' `lssentially the purpose of the proportioning Yplate is to control the thickness of 'the rubber stock I3 (Fig. 2*) which constitutesthe under' tread of the tread assembly.-

I* Ythe operation of the apparatus, `hot-water is' `first circulated throughout Vthe lvarious chambers inthe die headV in order `towering up jthe temperature of the head to approximately .1756?. This vis necessary in order that the rubl"b er"compositions, will flow properly `when being 'extruded through the cavities. vDiiferenttypesof rubber Lcompositions are introduced into the {tu- Qbulaihentr'ance openings 3,' -Sv and #8 as shown in Vliigllle '1.1 ,"The stock which is fedto these open- ;ings'is usuallyin `the'form of -a-ribbon of predetermined siZ'eWhiCh is cut'from a'warming mill and ;fed continuou'slyV to the tubers during their eration. Each 'of th'epdiierent rubber lcompo'- fsitions is forced 'through the cavities until Lit ymerges with theothers in' the prefer-ming' die sa. frrjnreafter the maladie-45 forms lthe desired .prole `of the tread -such'as Ishownfin Figure 2-.

t As the ituber continues in operation, the iiow v of rubber through the cavities `rgenerates considera'ble heatin'the die head and'it becomes necessary toflower the temperatures of the water being introduced into `the water circulating `cavities. The temperature .of the water-introduced-is such .that'thedischarge temperature o f thewater -will 111e @between .12513'. and 17.5?.

' A's'gbe'fore stated, the location ofthe spl-icefI-E '(Eig'. 2)l is critical. As soon as the `tuber begins the weXtrullding operation, the -proper nlocation 'of the splice [Epinay 'be measured and this line-lof -demarcationfmay 'be varied by l'mere-1y turning V'the hex nut""31"l(F,ig. 6*) and the Aadjustnlent may nomade while the tuber is in operation. y

,The adjustment for varying the thickness of lthe rubberv composition I3 (Fig. A2) referred Lto 'as Lthe' under .tread ris madei'by varyingthe position oftheproportioning plate 48 (Fig. 5). jT-his adjustment caribe made, howevenonly'uponsrev ,moval of the preforming die 43 and wh e the tuberisnot in'o'peration. t

Thediehead of my invention results i-nan'unusual combination for eiTec-ting the manufacture of composite treads in ahighly efficient and economical manner. It" is to be understood that `thednv'ention -may be mod-ined in accordance with the spirit of the invention and asappearing in the `appended claims.

Having thus described my invention what I -Lclam anddesire to protect .by Letters Patent is: i 1. An apparatus Vfor extr'uding .composite ,mavrt-,erials comprising, a dieA head, Ea pluraliyof invdependent extruders Yconnected with the die head, said die head having `passageways communicating with each. extruder, and each pas- .-sageway communicating fa common v, opening, a-,slid-ing bar positionedbetween the termination of the passageways and the common opening, and a projection from said sliding bar forming a wall between two of the passageways for varying the location of the junction between said two passageways.

2. An apparatus for extruding composite materials comprising, a die head, a plurality of int dependent extruders connected with the die head, walls form-ing passagewa-ys in vsaid rdie head, Qsaid `.passageways forming a. vcommullzicf tion' with each extruder and terminating ata common-opening, a wall portion positioned 'ibestween two of -said 4passageways for defi-ning the junction between two composit-ions of uthevcomposite material and means connected to .said wall 'portion extending to the outside of said diei-head -for adiustably positioning said wall --portion `to .vary the junction vbetween l said two passageways. :3. -apparatusfor extruding composite ma- ;terialsfcomprisingfa .die head, a plurality'of independen-tiextruders'connected-with the dieghead, wallsiorming jpassageways in vsaid .die fhead, said passageways :forming a Icommunication wlith each `extruder and Lterminating at a common yopening, an .adjustable wall portion positioned between two of said passageways for defining-the junction between two compositions-of the composite material,- land-means-extending to 4the outsido -of `the die:y head for Varying the position of -the adjustable wall portion. 4. Anf-'apparatus for extruding composite imalterials comprising, adie head, -a plurality ofindependent V.extruders .connected with the A'die head, walls forming passageways in said die head, -said passageways vforming a communica.- tion Iwit-h each extruder land terminating 4-at a :common-opening, and -a 'plate within `said -die head between the .termination .of one .of VVsaid -passagewaysand the commonopening and parf-tially Aobstructing communication between said --extruder-and l:terminating at a lcommon opening,

ianfadjustaibleproportioning .plate in communica- Vtionlwith one of the passageways .for gauging v@the 'thickness vof vthe Acomposition passing :through `said passagewaman adjustable wal'l'p'ortioniposftioned :between twovofsaid passageways foriden lng the fjunctionbetweenftwo compositionsfof 7A:the Vcomposite.materiaL andY means for varying fthe .position ofthe adjustable wall portion.

"5.6. .An :appara-tus. for.l extruding -composite :materialsfcomprising va ldie head, a plurality erfindependent :extruders connected with'the 'die head.

walls: forming'passageways in said Idie head, said passageways forming a communicationwitheach extruder and 1 terminating Vat .a common ropening, a separate block constituting apreformingzdie VApositioned at the: common opening of the .passageways, .and an adjustable Wall portion Vmounted Jbetween 'said -common opening and said sepa-rate v:'.blockand positionedfbetween two of said passage- Ways ifor dening'f-.the junction between two compositions Vof the composite material.

l'7. An apparatus for extrudingcomposite materials-comprising, afdie head, a plurality of Vindependent extruders .connected with the die ahead, -.wal1s for-ming passageways in said die head, .said passageways forming a communication with each extruder and terminating at a common opening, a separate block constituting a preforming die positioned at the common opening of the passageways, a proportioning plate adjustably attached to the preforming die for gauging the thickness of the composition passing through one of said passageways, and an adjustable wall portion positioned between two of said passageways for defining the junction between two compositions .of the composite material.

8. An apparatus for extruding composite mate- -rials comprising, a die head, three independent extruders Vhaving their axes radially extending from and connected to the die head, said die head lcomprising a block including walls dening passageways horizontally communicating with each extruder and terminating in a common opening at right angles thereto. an upper member and a lower member constituting the die headI block, Va triangular shaped bar having its base resting between the upper member and said separate block and having two of its sides forming a continuation of the walls of said passageways, said triangular shaped bar having a bore therein, and

a conduit communicating with the bore for circulating fluid through the bore.

against the lupper member with its adjacent sides 'I `forming a continuation of the walls of said passageways, and a projection extending from the triangular shaped bar for forming a divisional wall between two of said passageways.

9.. An apparatus for extruding composite materials comprising, a die head, three independent extruders having their axes radially extending" from and connected to the die head, said die head .comprising a block including Walls defining passageways .horizontally communicating with each 4extruder and terminating in a commonvopening at right angles thereto, an upper member and a lower member constituting the die head block, a triangular shaped bar having its base resting against the upper member with its adjacent sides .forming a continuation of the walls of said passageways, a projection extending from the triangularshaped bar for forming a divisional wall between two of said passageways, and an adjusting means for moving the triangular shaped bar -ina longitudinal direction for varying the position of the projection constituting the divisional wall between said passageways. 1

A10. An apparatus for extruding composite ma- .terials comprising, a die head, three independent .-extruders having their axes radially extending from and connected to the die head, said die head -,comprising a Yblock including walls defining passageways horizontally communicating with each lextruder and terminating in a common opening atright angles thereto, an upper member and'v a lower member constituting the die head block,

.a tseparate block constituting a preforming die positioned at the common opening of the passageways, a triangular shaped bar interposed between the upper ymember and said separatev block -and having two of its sides forming a continuation of the wallsv oi said passageways, and a projection extending from the triangular shaped bar for forming a divisional wall betweentwo of said passageways. 1l. An apparatus for extruding composite materials comprising, a die head, three independent extruders having their axes radiallyf extending vfrom and connected to the die head, said die head tcomprising a block including walls dening pas- .sageways horizontally communicating with each extruder and terminating in a common opening at right angles thereto, an upper member and a lower vmember constituting the die head block,

.a separate block constituting a preforming die positioned at the common opening of the passageways, a triangular shaped bar interposed 12. An apparatus for extruding composite materials comprising, a die head, a plurality of independent extruders connected with the die head, said die head having passageways communicating with each extruder, and each passageway communicating with a common opening, an adjustable wall portion positionedbetween two of said passageways for dening the junction between two compositions of the composite material and means extending from said adjustable wall portion to .the outside of the die head for varying the position of said adjustable portion.

13. An apparatus for extruding composite materials comprising, a die head, a plurality of independent extruders connected with lthe die head, walls forming passageways in said die head, said passageways forming a communication with each extruder `and terminating at a common opening, a separate block constituting a preforming die positioned at the common opening of the passageways, an adjustable proportioning plate Within said preforming die for gauging the thickness of the composition passing through one of said passageways, a final die plate in engagement with said preforming die, and an adjustable wall portion positioned between two of said passageways for defining the junction between two compositions of the composite material.

14. An apparatus for extruding composite materials comprising, a die head, three independent extruders having their axes radially extending from and connected to the die head, said die headA comprising a block including walls deni REFERENCES CITED The following references are of recordin'the le of this patent:

UNITED STATES PATENTS Number Name Date 1,952,469 Snyder et al Mar. 27, 1934 '2,096,362 Lehman Oct. 19, 1937 V 2,444,831 Kilborn July 6, 1948 FOREIGN PATENTS Y Number Country Date l.

138,557 Great Britain Feb.l 12, 1920 423,380

Great Britain Jan. 31, 1935 

